#include <stdio.h>

double sum(int);

int main()
{
    printf("%lf\n",sum(11));

    return 0;
}

double sum(int num)
{
    if(num == 0)
        return 0.0;
    int total = 0;
    for(int i = 1;i <= num;i++)
        total += i;

    return 1.0 / total + sum(num - 1);
}
